loss

n.

Old English los "loss, destruction," from Proto-Germanic *lausa- (see lose). The modern word, however, probably evolved 14c. with a weaker sense, from lost, the original past participle of lose. Phrase at a loss (1590s) originally refers to hounds losing the scent. To cut (one's) losses is from 1885, originally in finance.

at a loss

1.

Below cost, as in The store was doing so badly that it was selling merchandise at a loss.

2.

Puzzled, perplexed, in a state of uncertainty, as in When his letters were returned unopened, John was at a loss as to what to do next. This usage was originally applied to hounds who had lost the scent or track of their prey.
[ Mid-1600s
]

3.

at a loss for words. Unable or uncertain as to what to say. For example, Father's tirade left us all at a loss for words.
[ Late 1600s
]